What is a cancer
A mutation of cells caused by many different things.
Cancer June 22 - July 22
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Cancer is simply cells that won't die.
Normally, the cells in your body are programmed to die and be replaced. But in cancer, the "planned cell death" doesn't happen. Instead, they keep on living, and then the begin to replicate other cells that also don't die. Those un-dead cells are cancer cells.
Basically: uncontrolled cell growth. A mutation happens inside a cell, and it starts multiplying reallly fast, so all of those cells form a tumor--like a lump that's not normal. Sometimes, that tumor doesn't spread and can be removed without much problem. But sometimes, that tumor spreads to other parts of the body--or it grows in a part of the body that's hard to do surgery on, like the brain. Then, cancer can be very dangerous.
Cancer is a large group of diseases characterized by the common symptoms of uncontrolled (often rapid) cell growth and the ability to spread.
On a microscopic level cancer cells have the following characteristics:
1) immortality - normal cells obey a program of when to divide and how many generations. In cancer cells, these instructions are altered or ignored.
2) nuclear atypia - the accumulation of genetic mutations causes cancer cells to look abnormal usually an oversized nucleus
3) metastasis (for tumors) - the ability to spread to other organs
4) cell adhesion (for tumors) - normal cells are not directly connected to each other. There is an extra cellular matrix between them. For cancer cells, they are ability to be in contact with their neighbor cells.
On a molecular level, cancer is cells which have 2 sets of genetic mutations: oncogenes which promote cell growth and tumor suppressor genes which normally prevent cancer from developing typically by self-destructing rather than let mutations accumulate.